Evaluation and reinforcement according to the turkey building earthquake code 2018 of a school building in the intensive earthquake region

Earthquake has played an important role as one of the biggest problems throughout the history of humanity from past to present. Since people lived in large communities increased the devastating effects of the earthquake. So many research and studies were conducted by earthquake engineers and scientists to reduce destructive effects of the potential earthquakes. In the light of that works, earthquake engineers and scientists made numerous earthquake regulations which are directly binding rule for designing and implementing in a construction process by the impact of the earthquake. But, when we look past, mistakes in construction process and inadequacies of the regulations could not totally prevent harmful effect of it. In this thesis study, a school building is in the centre of the research, which was constructed in 1996 in accordance with regulations for the structures to be built in disaster areas 1975 (ABYYHY-1975) in Eyüp district of Istanbul. The Earthquake resistance of both existing and retrofitting state of the school building was analysed by using linear and nonlinear analysis methods. The building is 45 meter in long direction and 40 meter in short direction, which is 10.08 meter in its height. Based on the TBDY-2018, two calculation methods are used in this thesis study, which are Strength-Based Design Approach (DGT) and Deformation-Based Design Approach (SGDT). This thesis study is categorized in five sections. In the first chapter, seismic analyses and strengthening studies of existing buildings in previous years are presented in summary. It includes that what kind of technical details and calculation methods are taken place in TBDY-2018 for the current buildings. Moreover, gathering information from the buildings, determining level of damage, analysis methods and targeting capacity of earthquake resistance of existing buildings are also mentioned in this section. In the second chapter, details of performed studies at the school building constructed in 1996 are shown. The studies consist of destructive test and non-destructive test, which are directly related to determine mechanical properties of construction materials of the existing building. The tests are concrete core sample, reinforcement sample, scrapings of concrete cover, rebar readings with electronic device and Schmidt hammer test. Thanks to the works carried out, laboratory results were obtained. Then the mechanical properties were determined with the experimental data. In the third chapter, the model of existing educational institution building has been created by using SAP 2000 structural analysis software. According to TBDY-2018, linear and nonlinear analysis have been made. Equivalent earthquake load method has been used for linear analysis; on the other hand, static pushover and time history methods have been used for nonlinear analysis. With the received information from TBDY-2018, there were two performance level that we have tried to ensure safety condition to limit damage level for the three-story educational institution building. For the first performance level, it has been wanted to provide controlled damage performance level (KH) with a 2% probability of exceeding in 50 years earthquake ground motion level (DD-1) for TBDY-2018) in control of boundary conditions of non-linear analysis. For the second one, it has been desired to ensure limited damage performance level (SH) with a 50% probability of exceeding in 50 years earthquake ground motion level (DD-3) for TBDY-2018 under the same analysis conditions. However, due to the long-drawn-out of analysis process, it was only examined whether the earthquake ground motion level (DD-1) was achieved according to the controlled performance target. In the last chapter, results, comparisons and suggestions were clearly presented. It was obviously observed that developing strengthened model showed more rigid behavior, the displacements remain within the optimum limits of the structure, loads on the columns and beams were less, and the damages were less. The same cannot be said for the current state of the building. Performed retrofitting works had glorious impact on limited area of damage for the existing building. Furthermore, the controls of how much the base shear forces and displacements that could occur after the effects of the earthquake had been minimized in the structure were carried out for both cases. In the light of the obtained comparison from this thesis study, strengthening is extremely important in order to minimize the permanent damage caused by earthquakes with the increasing building stock. So, it is economically aimed to strengthen today's existing structures, which were built without due care and with taking into account the old regulations. It is emphasized that all damaged structures can be saved with retrofitting works to protect security of life. Consequently, it is clearly seen that strengthening that gives better results against earthquake, which is overemphasized in the new regulation.